(a) Technical Field
The present disclosure relates to a liquid crystal display.
(b) Discussion of the Related Art
Liquid crystal displays (LCDs) are now widely used as flat panel displays in various kinds of electronic devices. A liquid display typically has two display panels on which field generating electrodes such as pixel electrodes and a common electrode are formed, and a liquid crystal (LC) layer that is interposed between the panels. The LCD generates an electric field in the LC layer by applying voltages to the electrodes, and obtains desired images by controlling the strength of the electric field for determining orientations of LC molecules and polarization of light incident on the LC layer to vary the transmittance of light incident on the LC layer.
The liquid crystal display further includes switching elements that are respectively connected to the pixel electrodes, and a plurality of signal lines such as gate lines, data lines, or the like, that control the switching elements to allow a voltage to be applied to the pixel electrodes.
Among these liquid crystal displays, a liquid crystal display of a vertically aligned (VA) mode has been spotlighted because it has a large contrast ratio and a wide reference viewing angle, in which long axes of the liquid crystal molecules are perpendicular to the upper and lower display panels in a state in which an electric field is not applied. In this case, the reference viewing angle refers to a viewing angle at which a contrast ratio is 1:10 or to a luminance inversion limit angle between grays.
As methods of achieving a wide viewing angle in a liquid crystal display of a vertically aligned mode, there are a method of forming a cutout in a field generating electrode, and a method of forming a protrusion above or below the field generating electrode. Since the cutouts and the protrusions determine a tilt direction of the liquid crystal molecules, the tilt direction of the liquid crystal molecules is decentralized by appropriately disposing the cutouts and the protrusions, thereby widening the reference viewing angle.
The cutouts or the protrusions decrease the aperture ratio, however. In order to increase the aperture ratio, a structure having an ultra-high aperture ratio has been suggested for increasing a size of the pixel electrode to its maximum value. In this case, however, since the distance between the pixel electrodes is short, a strong lateral field is generated between the pixel electrodes. Alignment of the liquid crystal molecules is the scattered due to this lateral field and, as a result, texture or light leakage occurs.
Furthermore, liquid crystal displays of a VA mode have poor lateral visibility as compared to a front visibility. For example, in a liquid crystal display of a patterned vertically aligned (PVA) mode, which is provided with the cutouts, images gradually become brighter in a lateral direction. In the worst case, a luminance difference between high grays does not exist and, thus, pictures may be viewed in a state in which they are broken up.
Therefore, exemplary embodiments of the present invention have been made in an effort to provide an electrode arrangement having advantages of reducing loss caused by texture and thus improving an aperture ratio and transmittance.